Semiconductor technologies are continually progressing to smaller feature sizes, down to 65 nanometers, 45 nanometers, and below. A patterned photoresist layer used to produce such small feature sizes typically has a high aspect ratio. Maintaining a desired critical dimension (CD) can be very difficult for various reasons. For example, when a chemical amplified photoresist layer is used, the patterned photoresist layer can have a top rounding profile.